Eccentric and follower mechanism



Oct. 6, 1953 J. L. EDELEN 2,654,266

ECCENTRICAND FOLLOWER MECHANISM Filed July 12, 1951 2 Sheecs-Sheet l 22' INVENTOR.

33 JAMES L. EDELEN ATTORNEY J. L. EDELEN ECCENTRIC AND FOLLOWER MECHANISM Oct. 6, 1953 2 Sheets-Sheet 2 Filed July 12, 1951 FIG.4.

m u u I FIG.6.

INVENTOR. JAMES L. EDELEN fiflf 51 ATIQRNLY V Patented Oct. 6, 1953 UNITED STATES PATENT OFFICE James L. Edelen, Kirkwood, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a

corporation of Delaware Application July 12, 1951, Serial No. 236,408

7 Claims.

This invention relates to eccentric and follower mechanisms, and particularly to means for reducing wear and increasing the life of such devices.

Conventional fuel pumps and vacuum booster pumps in use on internal combustion engines are frequently actuated by a lever resiliently urged into contact at one end with an eccentric mounted on the engine cam shaft. In the conventional construction a fiat surfac of the lever makes a line contact with the face of the eccentric. Since the entire load is applied to an extremely small bearing area, wear on the bearing surfaces is very severe, particularly on the lever, which eventually may wear completely through. Wear, however, is not confined to the lever contact face, but also is very severe on the eccentric surface, substantially reducing the diameter thereof, as well as causing the cutting of grooves therein due to irregularity in the wearing down of the lever.

It is, therefore, the object of this invention to provide means for increasing the service life of eccentric operating mechanisms for pumps by eliminating the excessive wear inherent in the bearing surfaces of present types of eccentric and follower mechanisms.

A further object is to provide means whereby the permissible load on eccentric and follower mechanisms of this type may be substantially increased.

A further object is to provide a slow-wearing cam follower device which may be readily substituted for the present conventional followers in pump operating mechanisms, without any alteration to the eccentric or pump construction.

I achieve the above objects by providing the pump operating lever with a slidably or pivotally mounted contact shoe having a concave arcuate contact face, the arc of the contact face being the same radius as the eccentric. The mating arcuate faces of the shoe and eccentric thus provide a large bearing areaas compared with the line contact of the conventional structure, thereby distributing the load over the entire area without concentration on any restricted portion thereof as in the present construction. With the slidably mounted shoe an equally large bearing surface may likewise be provided between the fiat undersurface of the shoe and the surface of the lever, thus permitting similar load distributions and similarly inhibiting wear.

Other objects and advantages will appear from the specifications when read with the accompanying drawing, in which:

Fig. 1 shows one form of slidably mounted contact shoe and operating lever applied to a conventional diaphragm type pump.

Fig. 2 is an enlarged sectional view of the lever and shoe illustrated in Fig. 1.

Fig. 3 is a transvers section through Fig. 2 along the line 3-3.

Fig. 4 shows a modified form of slidably mounted shoe construction.

Fig. 5 is a transverse section along the line 5-5 of Fig. 4.

Fig. 6 shows another modification of slidably mounted shoe.

Fig. '7 is a transverse section along the line I--'I of Fig. 6.

Referring now to Figs. 1, 2 and 3, the numeral I I refers to an eccentric. A conventional diaphragm type pump I5 formed with a mounting bracket I6 includes a diaphragm (not shown) and operating stem I9, secured at its lower end to the diaphragm. I

Pump operating lever 22 is a curved, channelshaped sheet metal member formed with a central opening 23 through which passes journal shaft 24. One end of lever 22 is bifurcated as at 25 to receive operating stem I9. Stem I9 is formed with a head 26, against which is seated metal washer 21, resilient washer 28, and hard plastic washer 29. A coil spring 30 normally biases the diaphragm and its stem I9 downwardly, thus urging washer 29 into contact with the upper surface of the bifurcated portion 25 of lever 22.

A contact shoe 3| formed with a concave arcuate upper face 3| :1; for engagement with eccentric I I, and a plane lower face 32 for engagement with the web portion of lever 22, is slidably secured to lever 22 by a pin 33 which is mounted for slidable movement in longitudinal slot 34 in the end portion of the web of lever 22. The contact shoe 3| extends laterally at each side of the longitudinal side edges of the channel-shaped operating lever 22 and is provided with depending side flanges which embrace th side edges of the lever 22 to retain the shoe against lateral displacement. The depending side walls of the shoe 3| are so positioned with respect to the side walls of the lever as to provide suitable clearance to prevent binding during the sliding movement of the shoe on the bearing face of the lever. The bearing face of the lever is illustrated as a flat surface at the end portion of the lever structure.

The concave arcuate face 3Ia of shoe 3| is of the same radius as eccentric I I and is urged into contact with the surface of eccentric II by coil spring 35, one end of which is seated in a recess 36 in pump bracket I6, the other end being seated against the lower surface of the web of lever 22, about upturned locating member 31.

During operation of the engine, as eccentric i i rotates, shoe 3| remains at all times in contact with the eccentric and slides back and forth on lever 22 to accommodate itself to the movement of the eccentric. As has been indicated above, the arrangement provides large, long-wearing bearing surface both between the shoe and the eccentric and between the shoe and the lever.

A modified form of slidably mounted shoe is illustratd in Figs. 4 and 5. The shoe at is stamped out of sheet metal and 112.312.- concave arcuate upper face 4! for engagement with the cam surface. At either end ofthe arcuate surface, extending end portions-are bent under to form, with the bottom of the arcuate portion, a

relatively large, fiat bearing surface-.-for.slidable v engagement with the lever web. Downwardly extending flanges 42 are formed on either side-of the arcuate face, and tabs 4.3 extending inwardly fromirthe. lo'wercedge of reach -.thr; flanges. slidably.

secure the shoe togthe'lever... Tabsdsiride inia.

shallow notch 44 intheiflangeleverizf the ends of notch 44 serving."as- .;stops: on longitudinal movement :of the tabstand shoe.

Another form of slidably mounted shoe is shown intFigs; .6 and '7. In; this modification the.

shoe 45 is generally similar to .the' shoe of Figs.

1. -In a pump for operation by an engine rotated cam that is convex along its entire working surface, an operating lever mounted on a transverse pivot, a bearing surface formed at one end portion of said lever, a cam follower shoe having a bearing surface on one face in sliding contact with. said bearing surfacev of said lever, said cam follower'havinga second bearing surfacev formed as a section .of a cylinder and attached to said operating lever by a pin and slot connection positioned so as topermit sliding of the cam follower upon the lever in a plane parallel to theaxisof said transverse pivot and to permit the full area of said second bearing surface ofsaid foilowershoe: to remain in contact withthe working .surface. of-therotatable cam while spreading said leverbearing surface along a substantial portionof said lever.

2.In an eccentric and followermechanism, an

eccentric having a surface thatgis convex along its entire working periphery and follower mechanism-includin'ga levermember and a shoe memher, said shoe memberbeing formed with a concave surface for receiving theconvex surface of said ."eccentric, said lever gbeingformed with a bearing surface at one end portion upon which said shoe member. is supported for sliding movement so as to maintain said cam and shoe surfaces. in full surface engagement during oscillation of said lever, the end portions of said shoe memberprojectingtoward said lever bearing surface and being in sliding engagement therewith, and the longitudinal side faces of the shoe member being flanged downwardly to embrace the side of the lever member, one of said members being provided with spaced walls defining stops, and the other member having a projecting portion positioned between said stops, whereby a sliding movement of the shoe member on the bearing face of the lever is limited in both directions.

3. In an eccentric and follower mechanism, an eccentric having a surface; that is convex along :its entire working surface and follower mechanism including a lever member and a shoe member, said lever member being formed with a bearing surface-atone end portion upon which said shoe member is supported for sliding movement, .said shoe member being formed with a concave facefor receiving the convex surface of said eccentric in surface-contact relationship, the end portions; of the; shoe member being flanged downwardly for sliding movement with the hearing face of the lever, and the longitudinal side faces of the shoe member being flanged downwardly to embrace the sidescf-the lever member,

said lever memberv being formed with elongated... recessesdefined at;.their;.ends by wall portions, -1 and the flanged portions of the side faces of said;-

shoe member. being provided with-inwardly projecting tabs which travelbetween the walls. of. said recesses, thereby limiting the sliding move-1 mentof the.shoe on the lever..

4. In a fuel pump of the type-having'a housing and a lever pivotally mounted thereon witha projecting end-for. actuation'by an operating cam Y which is convex along its-entire working surface,

a bearing surface on saidend of said lever, anda cam follower shoe-carried onsaid bearing surface and having a concaveworking face for con-. tinuous surfacecontact. with the cam working surface, said shoe beingslidable longitudinally of. l the lever along said bearingsurface under the influence of, therotating cam associated therewith.

5. Eccentric and follower operating mechanism for a fuel pump comprising'a cam which is con vex along its entire workingsurface, a pivoted ing surface at one end-thereof, and a bearing shoe carried by said bearingsurface of said lever and having a concave workingface in continuous surface contact with said cam working surface, said shoe being mounted to slide back and forth in a direction longitudinally of said lever hearing surface during operation. a

7. Eccentric and follower operating mechanism for a fuel pump comprisinga cam which is convex along its entire working periphery and which is rotatable on a fixed axis, a pivoted lever with a bearing surface at one end portion thereof, and a wear shoe with a camengaging part in surface contact with saidcam, portions of the shoe being located at each side of the cam axis,

of the length of the lever.

JAMES L. EDELEN.

(References on following page) Number Name Date Salmon Aug. 17, 1886 Meehan Oct. 7, 1890 Worden et a1. June 27, 1893 Richards Aug. 4, 1903 Wadsworth Sept. 25, 1906 Melin Mar. 28, 1916 Dyson Mar. 22, 1921 Whitacre Sept. 1, 1925 Short Oct. 11, 1927 Michell Sept. 23, 1929 Number Number Name Date Newhouse May 24, 1932 Babitch Jan. 3, 1933 Runge July 3, 1934 Paxton July 9, 1940 Cofiey Feb. 13, 1945 Brooks Feb. 11, 1947 Rathbun Feb. 14, 1950 FOREIGN PATENTS Country Date Great Britain July 19, 1948 

